Not sure where to put this, again, sorry if I got it in the wrong place. Anyway, if you have a .rar that's a two-parter, as in, it needs the other one to extract or run and a prompt comes requesting it's location when you try to extract. Is there any way to get around that? It's very frustrating.
Try opening the first part. If it is the first part, it should request the next part. Just type in the location and name of the next part and you should be good to go. If you are missing parts, hopefully you have some PAR files that can be used to rebuild the missing/damage part with. Otherwise, you can just use the "Keep broken files" in the extraction screen to keep whatever you can get.